Channel change time is an important part of the user experience for digital video or other digital image or content applications. Channel change time represents a delay from the time that a viewer selects a channel for a digital video application to the time that corresponding video information is displayed to the viewer. Channel change time may be a function of many different elements such as tuner acquisition time, encryption descrambling, post-decode processing, and the time required to present the first picture to the viewer after finding a random access point in a video stream. The random access point represents a point in the video stream where a decoder may begin decoding successfully.
Normally, a channel change may comprise locating the random access point and filling a compressed data buffer (CDB) with data starting from this access point, decoding a coded picture, placing the decoded picture in a decoded picture buffer, and presenting the picture to the viewer. The picture is decoded and presented at a time indicated by clock references such as a decoding time stamp (DTS) and a presentation time stamp (PTS) transmitted together with the coded picture.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.